co-founding the rock band guster for gardner. ♪ ♪ ♪ >> we were touring heavily with my band, guster.falling in love with her, through osmosis, i was giving the environmental lens put-- you know, put in front of my eyes and started looking at the touring world. >> reporter: one look at the debris following an outdoor rock concert showed gardner the touring world wasn't exactly what you'd call sustainable. >> just looking at all the plastic on the ground, our tour buses with the generators never shutting off, d, you know, knowing that they don't get very good mileage. all the concessions, everything was just being thrown out and going right to landfill. and at the time, we-- we just shrugged our shoulders at each oer, going, it's just too bad it has to be this way. >> reporter: there've always been these two sides of rock and roll. there's trashing the hotel room and throwing the tv into the swimming pool, and the other side was, like, musicians for safe energy. >> the origin story of reverb is actually very much connected to that legacy. ♪ ♪ ♪ >> reporter: musicians united for safe en